Burner for producing glass fine particle deposited body, and device and method for producing glass fine particle deposited body

ABSTRACT

This burner for producing a fine glass particle deposited body is provided with a metallic gas-feed pipe that forms a burner body, and a cover for covering the gas-feed pipe, wherein: the gas-feed pipe and the cover are integrally formed; the gas-feed pipe has connected thereto a piping through which material gas, oxyhydrogen gas, and seal gas are supplied; and the cover covers, in the axial direction of the burner over a prescribed length and in a given constant outer diameter, the gas-feed pipe and a connection part of the piping connected to a lateral surface of the gas-feed pipe.

TECHNICAL FIELD

The present disclosure relates to a burner for producing a glass fineparticle deposited body, a device for producing the glass fine particledeposited body, and a method therefor. This application is based uponand claims the benefit of priority from Japanese Patent Application No.2018-227117, filed on Dec. 4, 2018, the entire contents of which areincorporated herein by reference.

BACKGROUND ART

Patent Literature 1 describes a burner for producing a glass fineparticle deposited body that forms the glass fine particle depositedbody by using siloxane as a raw material and a method for producing theglass fine particle deposited body.

Patent Literature 2 describes a burner that retracts as the glass fineparticle deposited body grows and of which a diameter increases.

CITATION LIST Patent Literature

Patent Literature 1: JP-A-2014-224007

Patent Literature 2: JP-A-2012-62203

SUMMARY OF INVENTION

According to one aspect of the present disclosure, a burner forproducing a glass fine particle deposited body includes:

a gas supply pipe which is made of metal and forms a main body of theburner; and

a cover that covers the gas supply pipe, wherein

the gas supply pipe and the cover are configured to be integrated,

a pipe for supplying raw material gas, oxyhydrogen gas, and seal gas isconnected to the gas supply pipe, and

the cover covers the gas supply pipe and a connection portion of thepipe connected to a side surface of the gas supply pipe with apredetermined length in an axial direction of the burner and a givenconstant outer diameter.

According to one aspect of the present disclosure, a device forproducing a glass fine particle deposited body, which produces the glassfine particle deposited body by depositing a glass fine particle on astarting rod disposed inside a reaction vessel, includes:

a wall portion that is disposed to be separated from the starting rodand includes a through hole through which a burner passes on a wallsurface;

a clean air supply portion that supplies clean air from an outside ofthe wall portion to an inside thereof;

the burner including a metallic gas supply pipe which is a main body ofthe burner, and a cover that covers the gas supply pipe and is formed tobe integrated with the gas supply pipe; and

a moving mechanism that retracts the burner as the glass fine particledeposited body grows, where

a pipe for supplying raw material gas, oxyhydrogen gas, and seal gas isconnected to the gas supply pipe of the burner, and

the cover covers the gas supply pipe and a connection portion of thepipe connected to a side surface of the gas supply pipe with apredetermined length in an axial direction of the burner and a givenconstant outer diameter.

According to one aspect of the present disclosure, there is a method forproducing a glass fine particle deposited body, which produces the glassfine particle deposited body by depositing a glass fine particle on astarting rod disposed inside a reaction vessel, the method including:

providing a through hole through which a burner passes on a wall surfaceof a wall portion disposed to be separated from the starting rod, theburner being provided with a metallic gas supply pipe as a main body ofthe burner and a cover that covers the gas supply pipe in an integratedmanner, a pipe for supplying raw material gas, oxyhydrogen gas, and sealgas to the gas supply pipe being connected to the gas supply pipe, thecover covering the gas supply pipe and a connection portion of the pipeconnected to a side surface of the gas supply pipe with a predeterminedlength in an axial direction of the burner and a given constant outerdiameter;

retracting the burner while keeping a gap with the through hole a givenconstant length as the glass fine particle deposited body grows; and

introducing clean air into the reaction vessel through the gap.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic configuration diagram of a device for producing aglass fine particle deposited body according to an embodiment of thepresent disclosure.

FIG. 2 is a schematic configuration diagram of a burner for producingthe glass fine particle deposited body according to the embodiment ofthe present disclosure.

FIG. 3 is a cross-sectional view taken along an arrow line C-C of FIG.2.

DESCRIPTION OF EMBODIMENTS Technical Problem

In an outside vapor deposition (OVD) method and a multi-burnermultilayer deposition (MMD) method, clean air is introduced into areaction vessel and then exhausted through an exhaust port provided atan opposite position, such that a glass fine particle or the like thatare not deposited on a glass fine particle deposited body (hereinafterreferred to as surplus soot) are exhausted, flame is adjusted, and theglass fine particle is stably deposited. Here, when the glass fineparticle deposited body grows and a diameter thereof becomes large, adistance between a burner and a deposition surface changes andtemperature of the deposit surface and deposition efficiency may change.Therefore, the burner needs to be retracted as the diameter of the glassfine particle deposited body increases.

When the glass fine particle deposited body is formed by using siloxaneas a raw material, it is preferable to provide a gap between the burnerand a wall surface around a periphery of the burner to flow clean airthrough the gap so that a stable air flow of the clean air can begenerated around the periphery of the burner.

Siloxane has a high boiling point and thus is required to heat Siloxaneat a high temperature, and when a quartz burner used in a process wheresilicon tetrachloride is used as a raw material is used, it is difficultto select a material to be used for connection with a pipe. Therefore,when siloxane is used, a metallic burner is used. When a long metallicburner with an outer diameter accuracy such as the quartz burner isproduced, it becomes very expensive. Therefore, a length of a fixeddiameter portion is shortened. Because of the length, it is difficult tosecure a stroke for the burner to be retracted only with the fixeddiameter portion, and a portion of the burner where the pipe isconnected other than the fixed diameter portion are also required topass through the wall.

Therefore, as the glass fine particle deposited body grows (the burneris retracted), a cross-sectional area of the gap through which the cleanair passes changes, a flow velocity of the clean air changes. When theflow velocity of the clean air changes and the air flow is not stable, adeposition state of the glass fine particles is affected. For example,in order to stabilize deposition efficiency, temperature of a depositionsurface needs to be kept within a certain range, but when thecross-sectional area of the gap changes during the deposition, thetemperature of the deposition surface may not be stable.

An object of the present disclosure is to provide a burner for producinga glass fine particle deposited body, a device for producing the glassfine particle deposited body, and a method therefor in which temperatureof a deposition surface of the glass fine particle deposited body can bestabilized during a producing process, and excess soot in a reactionvessel can be removed by efficiently performing exhaust.

<Advantageous Effects of the Present Disclosure>

According to a burner for producing a glass fine particle depositedbody, a device for producing the glass fine particle deposited body, anda method therefor, temperature of a deposition surface of the glass fineparticle deposited body can be stabilized during a producing process,and excess soot in a reaction vessel can be removed by efficientlyperforming exhaust.

DESCRIPTION OF EMBODIMENTS OF THE PRESENT DISCLOSURE

First, embodiments of the present disclosure will be listed anddescribed.

(1) According to one aspect of the present disclosure, there is a burnerfor producing a glass fine particle deposited body, the burnerincluding:

a metallic gas supply pipe which is a main body of the burner; and

a cover that covers the gas supply pipe, where

the gas supply pipe and the cover are configured to be integrated,

a pipe for supplying raw material gas, oxyhydrogen gas, and seal gas isconnected to the gas supply pipe, and

the cover covers the gas supply pipe and a connection portion of thepipe connected to a side surface of the gas supply pipe with apredetermined length in an axial direction of the burner and a givenconstant outer diameter.

According to the above-described configuration, the cover covers the gassupply pipe and the connection portion of the pipe connected to the sidesurface of the gas supply pipe with the predetermined length in theaxial direction of the burner and the given constant outer diameter.Therefore, even though the burner is mounted on one side wall surfacedisposed to be separated from the glass fine particle deposited body ina reaction vessel and the burner is retracted when the glass fineparticle deposited body is produced, a cross-sectional area of a gapbetween the wall surfaces can be made a given constant area. Since cleanair can be introduced through the given gap during a producing processby producing the glass fine particle deposited body using the burnerhaving the above-described configuration, temperature of a depositionsurface of the glass fine particle deposited body can be stabilized, andexhaust can be efficiently performed to remove excess soot in thereaction vessel.

(2) According to one aspect of the present disclosure, there is a devicefor producing a glass fine particle deposited body, which produces theglass fine particle deposited body by depositing a glass fine particleon a starting rod disposed inside a reaction vessel, the deviceincluding:

a wall portion that is disposed to be separated from the starting rodand includes a through hole through which a burner passes on a wallsurface;

a clean air supply portion that supplies clean air from an outside ofthe wall portion to an inside thereof;

the burner including a metallic gas supply pipe which is a main body ofthe burner, and a cover that covers the gas supply pipe and is formed tobe integrated with the gas supply pipe; and

a moving mechanism that retracts the burner as the glass fine particledeposited body grows, where

a pipe for supplying raw material gas, oxyhydrogen gas, and seal gas isconnected to the gas supply pipe of the burner, and

the cover covers the gas supply pipe and a connection portion of thepipe connected to a side surface of the gas supply pipe with apredetermined length in an axial direction of the burner and a givenconstant outer diameter.

According to the above-described configuration, in the burner mounted bypassing through a gap between the wall surface of the wall portiondisposed to be separated from the starting rod and the cover, the covercovers the gas supply pipe and the connection portion of the pipeconnected to the side surface of the gas supply pipe with thepredetermined length in the axial direction of the burner and the givenconstant outer diameter. Therefore, even though the burner is retractedwhen the glass fine particle deposited body is produced, across-sectional area of the gap between the wall surfaces can be made agiven constant area. As a result, since clean air can be introducedthrough the given gap during a producing process, temperature of adeposition surface of the glass fine particle deposited body can bestabilized, and exhaust can be efficiently performed to remove excesssoot in the reaction vessel.

(3) According to one aspect of the present disclosure, there is a methodfor producing a glass fine particle deposited body, which produces theglass fine particle deposited body by depositing a glass fine particleon a starting rod disposed inside a reaction vessel, the methodincluding:

providing a through hole through which a burner passes on a wall surfaceof a wall portion disposed to be separated from the starting rod, theburner being provided with a metallic gas supply pipe as a main body ofthe burner and a cover that covers the gas supply pipe in an integratedmanner, a pipe for supplying raw material gas, oxyhydrogen gas, and sealgas to the gas supply pipe being connected to the gas supply pipe, thecover covering the gas supply pipe and a connection portion of the pipeconnected to a side surface of the gas supply pipe with a predeterminedlength in an axial direction of the burner and a given constant outerdiameter;

retracting the burner while keeping a gap with the through hole a givenconstant length as the glass fine particle deposited body grows; and

introducing clean air into the reaction vessel through the gap.

According to the above-described method, in the burner mounted bypassing through the gap between the wall surface of the wall portiondisposed to be separated from the starting rod and the cover, the covercovers the gas supply pipe and the connection portion of the pipeconnected to the side surface of the gas supply pipe with thepredetermined length in the axial direction of the burner and the givenconstant outer diameter. Therefore, even though the burner is retractedwhen the glass fine particle deposited body is produced, across-sectional area of the gap between the wall surfaces can be made agiven constant area. As a result, since clean air can be introducedthrough the given gap during a producing process, temperature of adeposition surface of the glass fine particle deposited body can bestabilized, and exhaust can be efficiently performed to remove excesssoot in the reaction vessel.

(4) The method for producing the glass fine particle deposited bodyaccording to (3), where octamethylcyclotetrasiloxane (OMCTS) may be usedas a raw material and the gas supply pipe may be heated to 230° C. orhigher.

When OMCTS is used as the raw material, the gas supply pipe is heated to230° C. or higher, which is higher than boiling point temperature ofOMCTS, such that it is possible to prevent OMCTS from liquefying in thegas supply pipe, that is, in the burner.

Details of Embodiments of the Present Disclosure

A specific example of a burner for producing a glass fine particledeposited body, a device for producing the glass fine particle depositedbody, and a method therefor according to an embodiment of the presentdisclosure will be described with reference to the drawings.

The present invention is not limited to the examples, but is indicatedby the scope of the claims, and is intended to include all themodifications within the meaning equivalent to the scope of the claimsand within the scope thereof.

FIG. 1 is a schematic configuration diagram illustrating an example of adevice for producing a glass fine particle deposited body according toan embodiment of the present disclosure.

As illustrated in FIG. 1, a device for producing a glass fine particledeposited body 1 (hereinafter referred to as a producing device 1) is adevice for producing a glass fine particle deposited body M bydepositing a glass fine particle m on a starting rod 110 disposed in areaction vessel 100. The producing device 1 includes: a burner 2 thatsprays the glass fine particle m toward the starting rod 110; a wallportion 6 through which the burner 2 is inserted; a moving mechanism 7that moves the burner 2; and a clean air supply portion 8 that suppliesclean air.

A through hole is provided on an upper wall of the reaction vessel 100,and the starting rod 110 is disposed to be inserted through the throughhole in a vertical direction. An upper end of the starting rod 110 isgripped by a rotary traverse device (not illustrated), thereby rotatingin the reaction vessel 100 and reciprocating in the vertical direction.

The burner 2 is disposed on one side portion (a left side portion) ofthe reaction vessel 100, an exhaust pipe 101 is connected to a sideportion (a right side portion) thereof on a side opposite to the burner2, and the starting rod 110 is interposed therebetween. The exhaust pipe101 is a pipe that exhausts a predetermined amount of gas, and removesthe glass fine particle m, which is not deposited on the glass fineparticle deposited body M and floats in the reaction vessel 100, to theoutside.

The burner 2 is inserted through the wall portion 6 that partitions theinside of the reaction vessel 100 into two chambers, and is provided sothat a spraying surface of the burner 2 faces the starting rod 110. Aplurality of burners 2 (six in the present example) are provided to bearranged side by side at an equal gap in an axial direction (thevertical direction) of the starting rod 110. Each burner 2 is configuredto be able to independently spray the glass fine particle m toward thestarting rod 110.

The wall portion 6 is formed at a position separated from the startingrod 110. The inside of the reaction vessel 100 is partitioned, by thewall portion 6, into a reaction chamber 100A (a chamber on the rightside) where the glass fine particle m is sprayed and a clean air chamber100B (a chamber on the left side) into which clean air flows. A throughhole 61 is provided on a wall surface of the wall portion 6 to allow thetwo left and right chambers of the reaction vessel 100 to communicatewith each other. A plurality of through holes 61 (six in the presentexample) are provided to be arranged side by side at an equal space inthe axial direction of the starting rod 110. Each burners 2 are insertedinto the corresponding through holes 61. A diameter R1 of the throughhole 61 is formed to be, for example, about 70 to 80 mm.

The moving mechanism 7 is a mechanism capable of supporting the burner 2in a state of being inserted into the through hole 61, and moving theburner 2 backward (in a direction of an arrow A) or forward (in adirection of an arrow B) with respect to the starting rod 110 in thereaction vessel 100. The moving mechanism 7 is provided in, for example,the clean air chamber 100B. The moving mechanism 7 includes a drivingportion formed of, for example, a linear motor, a stepping motor, or thelike capable of moving the burner 2 linearly.

As such, the producing device 1 of this example produces the glass fineparticle deposited body M with an MMD method in which the plurality ofburners 2 allow the glass fine particle m to be deposited on thestarting rod 110 while relatively moving with respect to the startingrod 110.

The clean air supply portion 8 is a device for supplying clean air,which is cleaning gas, into the reaction vessel 100. The clean airsupply portion 8 is connected to the clean air chamber 100B via an airsupply pipe 81.

FIG. 2 is a schematic configuration diagram of the burner 2 observedfrom the side surface side. FIG. 3 is a cross-sectional view taken alongan arrow line C-C of FIG. 2. FIG. 3 illustrates a state where an areaoutside an outer peripheral side surface of a gas supply pipe 20, whenviewed from the direction of the arrow, is closed (blocked) by a cover30 with hatching of a broken line.

As illustrated in FIGS. 2 and 3, the burner 2 includes the gas supplypipe 20 and the cover 30 that covers a periphery of the gas supply pipe20.

As raw material gas, for example, octamethylcyclotetrasiloxane (OMCTS),the melting point of which is 17.5° C. and the boiling point of which is175° C., decamethylcyclopentasiloxane (DMCPS), the melting point ofwhich is −38° C. and the boiling point of which is 210° C.,hexamethylcyclotrisiloxane, the melting point of which is 64° C. and theboiling point of which is 134° C., hexamethyldisiloxane, the meltingpoint of which is −68° C. and the boiling point of which is 100° C., orthe like can be used, and OMCTS is the most desirable.

Siloxane as raw material gas, hydrogen (H₂), oxygen (O₂), or the like asflame forming gas, nitrogen (N₂) as seal gas, and inert gas such asargon (Ar) or the like are supplied to the burner 2. The burner 2 spraysvaporized siloxane into an oxyhydrogen flame generated by combustionsupporting gas (oxygen) and combustible gas (hydrogen), thereby causingoxidation reaction to make the glass fine particle m.

The gas supply pipe 20 is a portion forming a main body of the burner 2,and is formed in, for example, a cylindrical shape. The gas supply pipe20 is made of a metal material, for example, stainless steel or the likehaving excellent corrosion resistance. A length L of the gas supply pipe20 in an axial direction (a left and right direction) is, for example,about 75 to 105 mm. The length L of the gas supply pipe 20 can bechanged, for example, depending on an amount of siloxane to be suppliedin order to secure heat capacity of the gas supply pipe 20.

On the side surface of the gas supply pipe 20, connection portions 21 ato 21 d to which the pipes for supplying oxyhydrogen gas and seal gasare connected are provided. For example, a pipe 22 a for supplying sealgas is connected to the connection portion 21 a. For example, a pipe 22b for supplying hydrogen gas is connected to the connection portion 21b. For example, pipes 22 c and 22 d for supplying oxygen gas areconnected to the connection portions 21 c and 21 d. For example, each ofthe connection portions 21 a to 21 d is formed to extend vertically froma side surface of the gas supply pipe 20 and then extend a connectionport to which each of the pipes 22 a to 22 d is connected toward a backsurface direction of the gas supply pipe 20.

The burner 2 includes a raw material gas port 23 for spraying siloxanewhich is raw material gas at a center thereof. A plurality of seal gasports 24 for spraying N₂ which is seal gas are concentrically disposedaround a periphery of the raw material gas port 23. A plurality ofcombustible gas ports 25 for spraying H₂ which is combustible gas areconcentrically disposed around a periphery of the seal gas port 24. Aplurality of combustion supporting gas ports 26 and 27 for spraying O₂which is combustion supporting gas are disposed in a double concentriccircle around a peripheral of the combustible gas port 25. A diameter ofthe raw material gas port 23 is, for example, about 1 mm or more and 4mm or less. Diameters of the seal gas port 24, the combustible gas port25, and the combustion supporting gas ports 26 and 27 are, for example,about 1 mm or more and 2 mm or less.

The seal gas port 24 is connected to the pipe 22 a via the connectionportion 21 a. The combustible gas port 25 is connected to the pipe 22 bvia the connection portion 21 b. The combustion supporting gas port 26is connected to the pipe 22 c via the connection portion 21 c. Thecombustion supporting gas port 27 is connected to the pipe 22 d via theconnection portion 21 d. The raw material gas port 23 is connected to apipe 22 e for supplying siloxane connected to the back surface of thegas supply pipe 20. Diameters of the pipes 22 a to 22 d are about ¼ to ⅜inch. A diameter of the pipe 22 e is about ¼ inch.

For example, the cover 30 is formed in a cylindrical shape having agiven constant outer diameter. The cover 30 is provided to cover anouter periphery of the gas supply pipe 20 and the connection portions 21a to 21 d with a predetermined length in a length direction (the leftand right direction) of the gas supply pipe 20. For example, the cover30 is formed to have a length equal to or longer than at least adistance at which the burner 2 moves (is retracted) with respect to thestarting rod 110.

The cover 30 is formed to be integrated with the gas supply pipe 20. Thecover 30 and the gas supply pipe 20 move together when the burner 2moves. A back surface side of the cover 30 formed in the cylindricalshape is in an open state. On the other hand, on a front surface side ofthe cover 30, an area excluding the front surface of the gas supply pipe20 housed in the cover 30, that is, an area outside the outer peripheralside surface of the gas supply pipe 20 is in a state of being closed(blocked). Therefore, when the burner 2 is observed from a front side,only the front surface of the gas supply pipe 20 is configured to beseen. The clean air sent from the clean air supply portion 8 into theclean air chamber 100B can flow into the cover 30 from the back surfaceside of the cover 30, and the clean air flowing into the cover 30 isprevented from flowing out of the cover 30 from the front surface sideof the cover 30.

An outer diameter R2 of the cover 30 is formed to be smaller than adiameter R1 of the through hole 61 of the wall portion 6, for example,by about 10 mm. Therefore, a gap S is provided between an outerperipheral surface of the cover 30 and an inner peripheral surface ofthe through hole 61 of the wall portion 6. The burner 2 is inserted intoa central portion of the through hole 61 so that a distance in a radialdirection of the gap S is equal over the whole periphery of the cover 30in the through hole 61 of the wall portion 6.

A heater (not illustrated), which is a heating element, is provided onan outer peripheral portion of the gas supply pipe 20 in order to keepthe temperature of the gas supply pipe 20 at a high temperature. As theheater, for example, a tape heater is used. When the heater isenergized, the gas supply pipe 20 is heated to reach, for example,boiling point temperature of siloxane or higher (when siloxane is OMCTS,the gas supply pipe 20 is heated to, for example, 230° C. or higher). Asa result, the siloxane in the pipe 22 e is heated to reach the boilingpoint temperature or higher, and the temperature of the siloxane ismaintained so that the siloxane does not liquefy in the pipe 22 e.

Next, a method for producing the glass fine particle deposited bodyusing the producing device 1 will be described. In the method forproducing the glass fine particle deposited body described below, OMCTSis used as siloxane of the raw material.

First, each burner 2 is moved by the moving mechanism 7 so that eachburner 2 inserted through the through hole 61 moves up to apredetermined position at the time of starting producing with respect tothe starting rod 110.

After that, clean air is supplied from the clean air supply portion 8into the clean air chamber 100B. The clean air supplied into the cleanair chamber 100B is introduced into the reaction vessel 100 through thegap S between the outer peripheral surface of the cover 30 of the burner2 and the inner peripheral surface of the through hole 61 of the wallportion 6. Since the gap S is formed so that a cross-sectional areaperpendicular to the axial direction of the burner 2 is a given constantarea, the clean air is uniformly introduced into the reaction vessel 100from the gap S during the producing process.

The gas supply pipe 20 is heated to 230° C. or higher by the heaterprovided on the outer peripheral portion of the gas supply pipe 20. Theburner 2 sprays flame forming gas, seal gas, raw material gas, or thelike. As a result, the raw material gas vaporized in the formed flamecauses oxidation reaction to make the glass fine particle m. The glassfine particle m is sprayed on the starting rod 110 and deposited on thesurface of the starting rod 110 and the glass fine particle depositedbody M grows.

As the glass fine particle deposited body M grows and a diameter thereofincreases, each burner 2 is retracted in the direction of the arrow A inFIG. 1 while keeping the cross-sectional area of the gap S between theouter peripheral surface of the cover 30 and the inner peripheralsurface of the through hole 61 a given constant area.

According to the burner 2 for producing the glass fine particledeposited body, the device 1 for producing the glass fine particledeposited body, and the method therefor as described above, the gassupply pipe 20 and the connection portions 21 a to 21 d of the pipes 22a to 22 d are covered with the cover 30 having the given constant outerdiameter R2. Therefore, when the burner 2 inserted through the throughhole 61 of the wall portion 6 is moved (retracted) along the throughhole 61, the burner 2 can be retracted so that the cross-sectional areaof the gap S between the outer peripheral surface of the cover 30 of theburner 2 and the inner peripheral surface of the through hole 61 becomesa given constant area. As a result, an air flow of the clean air flowingfrom the clean air chamber 100B into the reaction vessel 100 through thegap S can be uniform. Therefore, during the producing process, thetemperature of the deposition surface of the glass fine particledeposited body M can be stabilized, and the glass fine particle m can beefficiently deposited thereon. Exhaust can be efficiently performed fromthe exhaust pipe 101 of the reaction vessel 100, and the excess glassfine particle m in the reaction vessel 100 can be removed.

When the raw material gas is OMCTS, the gas supply pipe 20 is heated to230° C. or higher during the deposition of the glass fine particledeposited body M, thereby it is possible to prevent OMCTS fromliquefying in the gas supply pipe 20, that is, in the pipe 22 e.

In the above-described embodiment, the cover 30 is fixed to the gassupply pipe 20, but the present invention is not limited thereto. Thecover 30 may be fixed to, for example, a bracket provided in the movingmechanism 7 to support the gas supply pipe 20. In the above-describedembodiment, the MMD method is described as an example, but the presentinvention is not limited thereto. For example, the present invention canalso be applied to an OVD method in which the glass fine particle isdeposited in the same manner as that of the MMD method.

Hereinabove, while the present invention has been described in detailand with reference to specific embodiments, it is apparent to thoseskilled in the art that various modifications and corrections can bemade without departing from the spirit and scope of the presentinvention. The number, position, shape, or the like of theabove-described components are not limited to the embodiments, and canbe changed to the number, position, shape, or the like suitable forperforming the present invention.

The phrase that the outer diameter of the cover has a given constantlength does not indicate that the outer diameter thereof is strictlyconstant, and indicates that the outer diameter thereof may have a rangein which the effect of the present invention is exhibited.

REFERENCE SIGNS LIST

-   -   1: producing device    -   2: burner    -   6: wall portion    -   7: moving mechanism    -   8: clean air supply portion    -   20: gas supply pipe    -   21 a to 21 d: connection portion    -   22 a to 22 e: pipe    -   23: raw material gas port    -   24: seal gas port    -   25: combustible gas port    -   26, 27: combustion supporting gas port    -   30: cover    -   61: through hole    -   81: air supply pipe    -   100: reaction vessel    -   100A: reaction chamber    -   100B: clean air chamber    -   101: exhaust pipe    -   110: starting rod    -   m: glass fine particle    -   M: glass fine particle deposited body    -   S: gap

1. A burner for producing a glass fine particle deposited body comprising: a metallic gas supply pipe that is a main body of the burner; and a cover that covers the gas supply pipe, wherein the gas supply pipe and the cover are configured to be integrated, a pipe for supplying raw material gas, oxyhydrogen gas, and seal gas is connected to the gas supply pipe, and the cover covers the gas supply pipe and a connection portion of the pipe connected to a side surface of the gas supply pipe with a predetermined length in an axial direction of the burner and a given constant outer diameter.
 2. A device for producing a glass fine particle deposited body, which produces the glass fine particle deposited body by depositing a glass fine particle on a starting rod disposed inside a reaction vessel, the device comprising: a wall portion that is disposed to be separated from the starting rod and includes a through hole through which a burner passes on a wall surface of the wall portion; a clean air supply portion that supplies clean air from an outside of the wall portion to an inside thereof; the burner that includes a metallic gas supply pipe as a main body of the burner, and a cover that covers the gas supply pipe and is formed to be integrated with the gas supply pipe; and a moving mechanism that retracts the burner as the glass fine particle deposited body grows, wherein a pipe for supplying raw material gas, oxyhydrogen gas, and seal gas is connected to the gas supply pipe of the burner, and the cover covers the gas supply pipe and a connection portion of the pipe connected to a side surface of the gas supply pipe with a predetermined length in an axial direction of the burner and a given constant outer diameter.
 3. A method for producing a glass fine particle deposited body, which produces the glass fine particle deposited body by depositing a glass fine particle on a starting rod disposed inside a reaction vessel, the method comprising: providing a through hole through which a burner passes on a wall surface of a wall portion disposed to be separated from the starting rod, the burner being provided with a metallic gas supply pipe as a main body of the burner and a cover that covers the gas supply pipe in an integrated manner, a pipe for supplying raw material gas, oxyhydrogen gas, and seal gas to the gas supply pipe being connected to the gas supply pipe, the cover covering the gas supply pipe and a connection portion of the pipe connected to a side surface of the gas supply pipe with a predetermined length in an axial direction of the burner and a given constant outer diameter; retracting the burner while keeping a gap with the through hole a given constant length as the glass fine particle deposited body grows; and introducing clean air into the reaction vessel through the gap.
 4. The method for producing the glass fine particle deposited body according to claim 3, wherein OMCTS is used as a raw material and the gas supply pipe is heated to 230° C. or higher. 